Warren D. Marcus^1,2, Rodger P. McEver³, Cheng Zhu¹

Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 245-252, 2004, DOI:10.3970/mcb.2004.001.245

Abstract When a cell adhered to another cell or substratum via surface proteins is forced to detach, lipid membrane tethers are often extruded from the cell surface before the protein bond dissociates. For example, during the inflammatory reaction leukocytes roll on the surface of activated endothelial cells. The rolling adhesion is mediated by interactions of selectins with their ligands, e.g., P-selectin glycoprotein ligand (PSGL)-1, which extrudes membrane tethers from the surfaces of both leukocytes and endothelial cells. Membrane tether extrusion has been suggested to regulate leukocyte rolling. Here we examine several factors that may affect forces required to initiate membrane tethers,… More >

Daxiang Cui¹, Cengiz S. Ozkan², Sathyajith Ravindran³, Yong Kong¹, Huajian Gao¹

Molecular & Cellular Biomechanics, Vol.1, No.2, pp. 113-122, 2004, DOI:10.3970/mcb.2004.001.113

Abstract Experiments on encapsulating Pt--labelled DNA molecules inside multiwalled carbon nanotubes (MWCNT) were performed under temperature and pressure conditions of 400K and 3 Bar. The DNA-CNT hybrids were purified via agarose gel electrophoresis and analyzed via high resolution transmission electron microscopy (HR-TEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that the Pt-labelled DNA molecules attached to the outside walls of CNTs could be removed by electrophoresis. The HR-TEM and EDX results demonstrated that 2-3% of the Pt-labelled DNA molecules were successfully encapsulated inside the MWCNTs. The experimental study complements our previous molecular dynamics simulations on encapsulation of single stranded… More >

M.V. Bayas^1,1, K.Schulten^2,2, D. Leckb,^3,3

Molecular & Cellular Biomechanics, Vol.1, No.2, pp. 101-112, 2004, DOI:10.3970/mcb.2004.001.101

Abstract The force-induced dissociation of the strand dimer interface in C-cadherin has been studied using steered molecular dynamics simulations. The dissociation occurred, without domain unraveling, after the extraction of the conserved trypthophans (Trp2) from their respective hydrophobic pockets. The simulations revealed two stable positions for the Trp2 side chain inside the pocket. The most internal stable position involved a hydrogen bond between the ring Ne of Trp2 and the backbone carbonyl of Glu90. In the second stable position, the aromatic ring is located at the pocket entrance. After extracting the two tryptophans from their pockets, the complex exists in an intermediate… More >

Yasuhiro Kajima, Miyabi Hiyama, Shuji Ogata

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.2, pp. 45-46, 2011, DOI:10.3970/icces.2011.018.045

Abstract There has been increased interest to understand through computer simulation the dynamics of micro-droplets; for example, the coalescence and/or disruption of water droplets as a fundamental process of the cloud formation for the earth climate estimation, the formation and size-controlling mechanism of the ink-droplet for advanced ink-jet printer. Since long-time simulations of such water droplets at atomistic scale are required, we often choose the rigid-body type inter-atomic potential as the TIP4P. In the present paper, we propose the improved angular-momentum Verlet (IAMV) method for the time evolution of the rigid molecules, by enforcing complete time-reversibility to the AMV method [1].… More >

Jiangguo Lin¹, Botao Xiao^1,2, Quhuan Li¹, Ying Fang¹, Jianhua Wu^1,*

Molecular & Cellular Biomechanics, Vol.15, No.1, pp. 37-49, 2018, DOI:10.3970/mcb.2018.015.037

Abstract The protein structure-function paradigm implies that the structure of a protein defines its function. Crystallization techniques such as X-ray, electron microscopy (EM) and nuclear magnetic resonance (NMR) have been applied to resolve the crystal structure of numerous proteins, provided beautiful and informative models of proteins. However, proteins are not intrinsically in static state but in dynamic state, which is lack in crystal models. The protein flexibility, a key mechanical property of proteins, plays important roles in various biological processes, such as ligand-receptor interaction, signaling transduction, substrate recognition and post-translational modifications. Advanced time-resolved crystallography has been developed recent years to visualize… More >

Hassan P. Modarres^∗, Mohammad R. K. Mofrad^†

Molecular & Cellular Biomechanics, Vol.11, No.1, pp. 39-65, 2014, DOI:10.3970/mcb.2014.011.039

Abstract Focal adhesions are the immediate sites of the cell’s adhesive interaction with the extracellular matrix and as such play a key role in mechanosensing and mechanotransduction at the edge of the cell interface with its surrounding microenvironment. A multitude of proteins orchestrate this mechanochemical communication process between the cell and its outside world. Filamin is a member of focal adhesion protein machinery that also plays a key role in regulating and bundling the acting filament network. A brief review is presented here on filamin and its important protein partners with the aim to shed light on the role of filamin’s… More >

T. Zhang^*

Molecular & Cellular Biomechanics, Vol.8, No.3, pp. 169-194, 2011, DOI:10.3970/mcb.2011.008.169

Abstract Cytoplasmic motion assumed as a steady state laminar flow induced by cytoskeleton stretching in a cell is determined and its effect on the mechanical behavior of the cell under externally applied forces is demonstrated. Non-Newtonian fluid is assumed for the multiphase cytoplasmic fluid and the analytical velocity field around the macromolecular chain is obtained by solving the reduced nonlinear momentum equation using homotopy technique. The entropy generation by the fluid internal friction is calculated and incorporated into the entropic elasticity based 8-chain constitutive relations. Numerical examples showed strengthening behavior of cells in response to externally applied mechanical stimuli. The spatial… More >

Fan Song^*

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 13-24, 2010, DOI:10.3970/mcb.2010.007.013

Abstract The electrostatic interaction effects including the interaction potential, force and torque between the neighboring chondroitin sulfate glycosaminoglycan (CS-GAG) molecular chains in the bottle brush conformation of proteoglycan aggrecan are obtained as the functions of the minimum separation distance and the mutual angle between the molecular chains based on an asymptotic solution of the Poisson-Boltzmann equation that the CS-GAGs satisfy under the normal physiological conditions of articular cartilage. The present study indicates that the electrostatic interactions are not only associated intimately with the separation distance and the mutual angle, which are shown as purely exponential in separation distance and decrease with… More >

Vedula S.R.K.^*, Lim T.S.^†, Hunziker W.^‡, Lim C.T.^§

Molecular & Cellular Biomechanics, Vol.5, No.3, pp. 169-182, 2008, DOI:10.3970/mcb.2008.005.169

Abstract Intercellular adhesion molecules play an important role in regulating several cellular processes such as a proliferation, migration and differentiation. They also play an important role in regulating solute diffusion across monolayers of cells. The adhesion characteristics of several intercellular adhesion molecules have been studied using various biochemical assays. However, the advent of single molecule force spectroscopy as a powerful tool to analyze the kinetics and strength of protein interactions has provided us with an opportunity to investigate these interactions at the level of a single molecule. The study of interactions involving intercellular adhesion molecules has gained importance because of the… More >

Shaohua Chen^*

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 97-106, 2008, DOI:10.3970/mcb.2008.005.097

Abstract Recently, contact mechanics has been widely used to get some understanding of the biological adhesion mechanisms, such as cell-cell adhesion, insects' adhesion and locomotion. JKR theory is usually adopted as a basis, in which the interaction of molecules is considered in contrast to the classical Hertz solution. In this paper, two problems are summarized, which may give some insights to cells or bio-molecules sensitivity to environmental signals: (1) cell reorientation on a stretched substrate; (2) spontaneous detachment between cells or bio-molecules under the variation of environmental signals. The intention here is only to illustrate the possibilities that contact mechanics may… More >